I have a PostGIS database and have successfully consumed a table into GeoServer and published a WFS. Are there REST endpoints available for these WFS' akin to ESRI's feature services? How are parameters to be constructed?

have you looked at this post? "Leaflet doesn't directly support WFS services on their own, but it will happily work with JSON data, fortunately GeoServer can output a WFS service as JSON"
– tomsJan 12 '15 at 19:27